In Gaza Tuesday, Israel kept up military pressure on Palestinians in an effort to free an Israeli soldier held captive by Palestinian militants since last week. For the seventh day in a row, Israeli planes bombed Gaza buildings, and talks to free the soldier broke down.

MICHELE NORRIS, host:

From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris.

Military ships from eight countries are gathered off the Hawaiian Islands for a big training exercise. This is the sound of the sonar they had hoped to use as part of the war games.

(Soundbite of sonar blip)

NORRIS: But now a federal judge has put a stop to those plans. NPR's Elizabeth Shogren

ELIZABETH SHOGREN reporting:

Rear Admiral James Simon says the Rim of the Pacific naval exercise is a crucial opportunity for the United States and its allies to practice warfare.

Admiral JAMES SIMON: This is a very critical exercise, one of the biggest ones we do. It's 40 ships, 8 nations.

SHOGREN: A key part of the exercise is seeking out enemy submarines, which are so quiet that even with sophisticated sonar, they're hard to track.

Admiral SIMON: Finding a submarine is one of the hardest things we do, so in just about all of our exercises, that anti-submarine warfare piece, including active sonar, is a very critical part of what we do.

SHOGREN: But yesterday, a federal judge in California ruled that, at least temporarily, the military can't use its sonar. She says an environmental group provided convincing evidence that the sonar is harmful to whales and other sea creatures.

That's what scientists have been saying for the last few years. They're not sure why sonar hurts whales, but it sometimes causes them to beach themselves or interferes with their ability to navigate, find food and care for their young.

The Navy has agreed to take precautions to avoid hurting whales, but the Natural Resources Defense Council decided the military wasn't doing enough, so it went to court.

Mr. JOEL REYNOLDS (National Resources Defense Council): Our position, fundamentally, is that whales and other marine species should not have to die for practice.

SHOGREN: Joel Reynolds is a lawyer for the environmental group. He says there's a long history of whales being hurt or killed after being exposed to sonar. For example, two years ago, the last time the military held this exercise off of Hawaii, more than 150 whales stranded themselves in shallow water and had to be rescued.

Mr. REYNOLDS: So there's no question any longer about the potential harm associated with this technology.

SHOGREN: Reynolds says it's particularly alarming for the Navy to use sonar in the waters off the Hawaiian Islands because they're home to such a uniquely rich assortment of marine life. In fact, the waters are so special that President Bush recently set aside a huge stretch of the Pacific as a National Marine Monument. The military's practice area overlaps with the new monument. Again, Reynolds from NRDC.

Mr. REYNOLDS: The president designated it precisely because it should be protected. And we think it makes no sense for the Navy to be using high-intensity, mid-frequency sonar anywhere near that area.

SHOGREN: The Navy was determined to evade the lawsuit, so on Friday it announced that the Defense Department had offered it an exemption from the Marine Mammal Protection Act. Again, Admiral Simons.

Admiral SIMONS: We issued the exemption to make sure that this exercise would go on.

SHOGREN: But the Navy's maneuvering fell short. The judge ruled that the military had violated another environmental law and she ordered the Navy to sit down with the environmentalists and come up with a plan to protect whales and other sea creatures from sonar.

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